Radio-goniometric system



Dec 18, 1951 P. BODEZ 2,578,966

RADIO-GONIOMETRIC SYSTEM Filed June 9, 1949 2 SHEETSSHEET 1 01 FE E D 0 o F i G 2 F F G 5 u RECEIVER DEVICE FOR RECEIVER ROTATING METER ANTENNAS S NTENNAS METER INVENTOR PBERRE BQDEZ a BY fi-TORNEY Dec. 18, 1951 BODEZ 2,578,966

RADIO-GONIOMETRIC SYSTEM Filed June 9, 1949 2 @HEETS-SHEET 2 F E g a V .5 F? B METER A34 TTORNEY Patented Dec. 18, 1951 UNITED STATES OFFHCE RADIO-GONIOMETRIC SYSTEM Application June 9, 1949, Serial No. 98,065 In France June 14, 1948 11 Claims.

1 The present invention relates to an improved radio-goniometer that has for its object to do away with the necessity of the so-called doubt removing operation; in other words, it gives out without any ambiguity the azimuth of the received field while eliminating reliably the opposite azimuth. This result is achieved through the cooperation between, on one hand a conventional system providing with an accuracy as high as may be desired, the direction sought for with an ambiguity of 180 by reason of the very large spacing that may be allowed for the aerials, and on the other hand a complementary arrangement defining the azimuth to be adopted for the direction given out by the first system, so as to retain only the actual azimuth sought for and possibly to wipe out other parasitical directions.

The invention resorts in particular to obtain this result to aerials of the well-known Adockyp The doubt-removing system is chiefly constituted by an Adcock aerial arrangement arranged outside the plane of the conventional system. For instance, two Adcock aerials may be used the vertical plane of which is preferably perpendicular to the conventional system providing accurately the direction but not the actual azimuth.

These Adcock aerials are connected through transmission lines of different lengths, whereby the waves passing through them are submitted to different delays or lags before they reach the receiver, the difference between the lags being actually adapted to make up for the difference between the moments at which the waves arrive at the two aerials when the plane of said aerials is directed towards the transmitter.

The spacing between the aerials is selected in a manner such that the diiference between the durations of travel may be equal e. g. to one quarter of a period. It is immediately apparent that this arrangement allows removing the doubt of 180 as to actual azimuth. As a matter of fact, in the case where the direction of the incoming. wave is such that the electromotive force induced in the first aerial is illustrated by the vector 0C1 as shown in Fig. 1 of accompanying drawings while the vector OD1 illustrates the voltage induced in the second aerial, the angle between the two vectors being equal to a, the transmission line connecting the first aerial to the receiver should introduce a supplementary lag that is precisely equal to the electrical angle a, so that the electric voltage fed to the receiver through the first aerial coincides, with a difference of 180 ascribable to the crossing provided through the conventional connection between the aerials of the Adcock system. with that fed through the second aerial. On the contrary, if the wave arrives from the opposite direction, the lags are added to one another instead of forming a difference and the electrical voltage fed to the receiver through the first aerial is illustrated by the vector OD symmetrical of CD1 with reference to 001 the datum-line being assumed to be OD1.

Consequently, the geometrical sum of O symmetrical of CD1, with reference to the point 0 and of OD is not equal to zero. This allows discriminating the two directions of which one provides at the receiver end, as disclosed, a zero voltage while the other provides a voltage different from zero under the sole condition that the angle a may be diffeffrent from 180 Obviously also it is of interest to select this angle or. approximately equal to 90 in order to obtain a maximum difference in the measurement so as to clearly eliminate the doubt as to azimuth as this leads to a phase shifting by one quarter of a period as disclosed hereinabove.

The invention will be better understood through the following disclosure given by way of example and referring to accompanying drawings, wherein:

Fig. 1 is a diagram illustrating the principle of the invention as disclosed hereinabove.

Fig. 2 illustrates a possible manner of distributing the aerials.

Fig. 3 is a wiring diagram incorporating the auxiliary doubt-removing aerial system.

Fig. 4 is a modification of Fig. 3. I

Figs. 5, 7 and 8 are further diagrammatic showings illustrating modifications of the invention.

Figs. 6, 9 and 10 are coresponding wiring diagrams.

Turning to Fig. 2, the vertical aerials are illustrated through their horizontal projections. A and B designate the two aerials of the conventional Adcock system providing with accuracy the desired direction that is defined through perpendicularity to the vertical plane containing A and B.

C and D designate the two aerials used for removing doubt as to azimuth, C being the first one and D the second one.

Fig. 3 is the corresponding wiring diagram in which are shown again the aerials A and B that energize in the conventional manner the detecting receiver E through the usual connections.

C and D illustrate the system of two aerials used for removing doubt as to azimuth. In this case, the connections between the aerials that are also of the Adcock type, are such that the contact points between said connections, that are crossed in the ordinary manner, and the line feeding the receiver, are shown as arranged in a very dissymmetric manner, In other words, the line F connecting the ends of the aerial C to the line U leading to the receiver R has a length that is very different from that of the line G connecting the aerial D with the line U, the diiierence in length between the lines F and G providing the phase shifting a. of Fig. 1 between the voltages provided by the dipole aerials C and D.

The spacing between the aerials C and D is equal to Z and the angle a is selected in a manner such that the above mentioned relationship may hold through as given out by the formula A being the wave length of the received field.

It is thus apparent that the direct current or low frequency voltages obtained at the output from the receivers E and R are simultaneously equal to zero only at the moment when the field received is perpendicular to the plane of the aerial AB and comes from the direction leading from C and directed towards D.

As a matter of fact, in the opposite direction, E provides, it is true, a voltage equal to zero, but R provides a voltage that is clearly different from zero, as explained hereinabove.

It has been stated that the phase-shifting is obtained by means of transmission lines of a different length, but obviously it is possible to use instead lines with different characteristics and also it is possible to introduce a phase shifting device in one of the lines or these various means may be associated in different manners. Similarly, the plane containing the aerials C and D does not require being perpendicular to the plane of the aerials A and B, although this manner of operating is more favorable. It is simply sufficient for the phase shifting provided by the differences in the duration of travel through the lines F and G to provide for the return of the sector C1 on to the vector ODl when the direction of propagation is perpendicular to the plane of the aerials A and B and coincides with one of the two corresponding azimuths.

Fig. 3 illustrates the conventional connecting means between the Adcock aerials forming each of the associated two systems. But it is possible to use advantageously the connecting means forming the object of applicants copending application Serial No. 98,066, filed June 9, 1949, entitled Directional Aerial System claiming priority of French patent to the Sadir-Carpentier Company of June 14, 1948. Such connections are illustrated in Fig. 4. In said figure, the aerials A and B are arranged as precedingly, except that their upper elements D are connected directly with one another while their lower elements are connected with the line feeding the receiver E.

The same connections are provided for the aerials C and D the upper elements of which are connected directly while the lower elements are connected with the receiver R through the line U, the connecting sections being of a different length in order to take into account as above the differences in the duration of travel.

In each embodiment, whether that of Fig. 3 or that of Fig. 4, the simultaneous wiping out of the voltages collected at the output of E and of R is defined through a device S that is well known per se for anyone skilled in the art and that it is not necessary to describe with any further detail. This device may, for instance, add up the direct current or very low frequency voltages fed 'by E and R and give out the moment when the resultant voltage is equal to zero.

The aerials A and B of the first system are spaced by a distance L. In conventional aerials of this type, this distance isselected at a value less than in order to, avoid any secondary zeros, corresponding to directions at an angle with the plane AB. This leads to a limitation of the accuracy of the measurements. This drawback is readily removed in the case of the present invention that allows in contradistinction using aerials A and B the spacing between which L is clearly larger than the above value suitably modifying the spacing between the aerials C and D that is the difference in phase shifting introduced through the lines F and G.

It will be finally remarked that the arrange ment according to the present invention provides the advantage of leading to the execution of a radiogoniometer that may be used within a very large range of wave-lengths to either side of the wave-length for which it is designed as provided through the fact that the differences between the duration of travel through the cables vary as a function of" the wave-length according to a r law such that these differences in the duration of travel make up, within a very extensive range,

for the variations depending on the wave-lengthsof the intervals separating the moments of arrival of the wave at the aerials of the doubtremoving system.

According to a modificationof the above arrangement, it is possible to reduce the supplementary doubt removing system to a single aerial.

This single supplementary aerial constituted preferably by a vertical dipole aerial, is arranged outside the plane connecting the two aerials, of the principal aerial system. Except for this condition, its location is selected ad libitum. It is, however, preferable, for reasons of bulk and symmetry, to locate it at the apex of an isosceles" triangle, that is at equal distances from the aerials of the main system as illustrated in Fig. 5 showing the projection of the aerials on a horizontal plane, A and B designating the main.

aerials and C the supplementary aerial- In the modification considered, the cables or lines leading to each of the three aerials are connected as disclosed in the above mentioned copending specification entitled Directional Aerial System.

This manner of connecting the aerials consists chiefly in providing a mounting under opposition conditions providing a zero current in the connecting leads at the moment of the measuring of the voltage.

Consequently, in accordance with the modification referred to, the leads of the three wires connected to the upper elements of the dipoles, are connected to a common point. The lower elements are connected respectively to two receivers providing across their terminals, a direct current of very low frequency voltage, said very low frequency being due to the rotation of the aerial around a vertical axis.

As in the case illustrated with reference to Figs. 3 and 4, the connections are established in a manner such that the voltages across the terminals of said receivers are simultaneously equal to zero only when the plane of the aerials AB is perpendicular to the direction of the field received, and latter comes e. g. from the side on which the suplementary aerial C is located.

The three lines from the aerials are given lengths between each aerial and the common point that are such that the differences in the duration of travel over said lines compensates for the differences between the moments of the arrival of the wave on the three aerials.

Fig. 6 illustrates the embodiment referred to hereinabove and applicable to the case where the plane of the aerial AB is perpendicular at the moment of the measuring to the direction of the field received. i and 2 designate the two elements of the aerial A and 5 and 6 the elements of the third aerial C that serves for removing doubt as to azimuth. The elements I and 2 are connected with the two wires 1 and 8 that may be constituted as well by coaxial cables, of a first line. Similarly, 3 and 4 are connected with the wires or cables 9 and ll! of a second line and the elements 5 and 6 are connected with the wires H and [2 of a third line. The wires I, 8 and 9, ill are given equal lengths and similar characteristics, so as to provide for the desired symmetry. On

the other hand, the wires ll, I2 have a length or characteristics such that the voltage across the ends of said wires ll, l2 opposed to the aerial end is in phase with the voltage across the corresponding ends of the wires 1-8 and 9-H! when the field received is perpendicular to the plane AB and comes from the same direction as the aerial C.

As disclosed with reference to the first embodiment of the invention, the ends of the wires 8-10 and I2 of the three lines are connected together while the ends 1 and 9 lead to one receiver E and the ends ll and 9 to a second receiver R. It is immediately apparent that these receivers play exactly the same part as precedingly. The receiver E measures the voltage between the aerials A and B and gives out the direction sought for with a possible error of 180 while the receiver R allows defining the exact azimuth by reason of the voltage fed to it being zero for the exact azimuth and different from zero for the opposed azimuth. The simultaneity of the appearance of the zero voltages in both receivers is measured as already disclosed through the device illustrated at S.

In this case again the spacing between the aerials A and B is not limited through the production of secondary axes and it is possible to resort preferably to a spacing C--H between C and the plane ABthat is equal substantially to one quarter of the wavelength of the received field.

- Many details may obviously be modified in either of the embodiments disclosed and for instance in the case of Fig. 5; the line ll-l2 may assume a size such that the receiver R receives a zero voltage when the wave comes fromthe side opposed to C with reference to A-IB. Similarly the part played by the leads |--9Il and 8I0-l2 may be reversed.

Fig. 6 as above described provides for a measuring in the case of the field received being perpendicular to the plane AB.; It will be remarked that within the scope of the present invention, it is possible to modify the relative sizes of the leads so as to execute the measuring for any angular setting of the plane of A--B with referenceto the direction of incoming field.

It is sufficient as a matter of fact to give the three connecting lines as disclosed lengths adapted to compensate, in the case of such an angularity, for the lapse of time between the arrival of the wavesat the three aerials. It will be remarked lastly that the embodiment of Fig. 6' retains the advantages relating to Figs. 3 and 4 concerning the large range of sound frequencies within which it may be advantageously used.

The above described embodiments require two separate receivers; now, according to a further modification, it is possible to do away with the additional receiver while retaining only three aerials. This result is obtained by resorting to an aerial system similarto that disclosed with reference to Fig. 6 wherein there are provided three identical aerials while the lines feeding the three aerials assume difierent lengths. In the present case, as'illustrated in Figs. 7 to 10, these lengths are reckoned in a manner such that the voltages across the ends of the lines may at the moment of the measuring be no longer in phase as hereinabove but'may form an actual three-phase system, in other words the voltages across the endsare shifted with reference to one another through In Fig. '7 of accompanying drawings are shown three vectors for an equilibrated three-phase system, that is three equal vectors shifted by 120 with reference to one another as illustrated at Oa--Ob'0c, said three equal vectors produces a geometrical sum equal tozero only if the three vectors are shifted by 120 with reference to one another.

The embodiment according ,to Figs. Q'and 10 relies on this well known fact.

Fig. 8 shows the three aerials A--B--C the relative arrangement of which is the same as in the case of Fig. 5. But in the present case the distance A-B is selected so as to bepreferably equal to one half of the wavelength. These three aerials are executed in a similar manner soas to produce across their terminals equal voltages.

Lastly, in the embodiment considered, it is not necessary but itis of advantage toresort to the connecting means described in above mentioned copending specification. p i

As a matter of fact, Fig. 9 shows an embodiment with conventional connections while Fig. 10 shows connections modified in accordance with the teachings of said copendingapplication.

In Fig. 9, the elements of the aerial A are again shown at l and 2, those'oi! the aerial B at'3 and and those of the supplementary aerial C at and 5. The lines I and 8, 9 and H), H and I2 connected respectively with the elements of the three aerials, have as disclosed lengths or characteristics such that the voltages across their ends that are opposed to the aerials form an equilibrated three-phase system when the wave comes in through a predetermined known direction.

At their outer ends, said three lines corresponding to the upper elements or to the lower elements are short-circuited. It is immediately apparent that under such conditions, the voltages across the terminals of the common end of the three lines corresponding to the upper and lower elements respectively are equal to zero only in the case considered. Said voltages are fed to the receiver E that feeds across its terminals a zero voltage when the system of three aerials is suitably directed, said angular setting removing the necessity of an actual doubt-removing system.

Fig. shows a system similar to Fig. 3 with however the difference that the connections are those disclosed in the above mentioned copending specification; the same elements may be found as precedingly while the lines have different lengths reckoned as disclosed hereinabove. However, in the present case, the lines are interconnected through their ends so as to provide a series connection as follows: the end of 8 is connected directly with the end of i2 so as to connect the upper ends of the elements 2 and 6 of the aerials of A and C. Similarly, the wires 9 and II are interconnected so as to connect with one another the lower elements 3 and 5 of the aerials B and C. Lastly, the single re-- ceiver E is connected across the extreme terminals constituted by the ends of the lines I and Ill connected respectively with the lower element I of the aerial A and the upper element 4 of the aerial B. I

Obviously moreover, it is possible to provide in various other manners the connections disclosed in Figs. 9 and 10, for instance it is possible to reverse the connections of one of the lines corresponding to one aerial, provided the length of said line is correspondingly modified.

A further examination of the modifications that may be brought to the last disclosed embodiments shows that it is always possible to obtain a single direction of zero voltage and only one with three aerials of any size whatever, provided only they do not lie in the same plane.

What I claim is:

1. A radio. goniometric receiver set comprising an Adcock aerial system including two. dipole aerials, a second Adcock aerial system including two dipole aerials, the plane of said second system being substantially perpendicular to the lane of said first system, means for rotating said systems in unison, a first receiver and a second receiver, means for connecting said first receiver with the two corresponding elementary dipole aerials of said first Adcock aerial system and means for connecting said second receiver with the two corresponding elementary dipole aerials of said second Adcock aerial system, means for introducing a'time delay in the waves fed from one of the dipole aerials in said second Adcock aerial system that is substantially equal to the time required for the waves traveling in the direction of the plane of said second Adcock aerial system to travel from one of the dipoles thereof to the other and means for adding the absolute 8 value of the signal voltages produced by the said two receivers. v

2. A radio goniometric receiver set comprising an Adcock aerial system including two two-element dipole aerials, a single complementary twoelement dipole aerial located outside the plane of aerials of the Adcock system, two receivers, means for connecting the three corresponding elements of each of said dipole aerials together, means for connecting said receivers selectively with the other elements of said two first aerials, means for connecting the other element of said complementary aerial to said receivers, means in said last mentioned means for introducing a time delay in the waves fed thereby corresponding sub stantially to the time interval required for the waves progressing perpendicularly to the plane of said Adcock aerial system to travel over the distance between said plane and said complementary aerial, and means for adding the absolute value of the signal potentials at the output of said receivers.

3. A radio goniometric receiver set comprising an Adcock aerial system including two two-element dipole aerials, at least one additional twoelement dipole aerial arranged outside the plane of said Adcock aerial system, means for rotating all of said dipole aerials in unison, receiving means and means for connecting said receiver with the elements of the difierent dipole aerials, said last mentioned means including means for altering the phase of the signal voltages supplied by selected ones oi said dipole aerials to said receiving means so that the output voltage of said receiving means is zero when the azimuth of the incoming waves registers with a predetermined axisof said rotating aerials.

4. A radio goniometric receiver set comprising an Adcock aerial system including a pair of twoelement dipole aerials, a supplementary two-element dipole aerial positioned outside of the plane of said .Adcock aerial system, a single receiver having a pair of input terminals, means for re tating said three aerials around a vertical axis, connections for connecting one of said terminals with one element of one of the dipole aerials of said Adcock aerial system and connections for connecting the other of said terminals with the opposite element of the other dipole aerial of said Adcock aerial system and connections for connecting the remaining upper elements of said dipole aerials and the remaining lower elements of said dipole aerials respectively with one another, the lengths of said connections being such as will provide a balanced three-phase system for a predetermined angular setting of the rotary system of aerials with reference to the incoming waves.

5. A radio goniometric receiver set comprising an v.Adcock aerial system including a pair of twoelement. dipole aerials, a supplementary twoelement dipole aerial positioned outside of the plane of said Adcock aerial system, a single receiver having a pair of input terminals, means for rotating said three aerials around a vertical axis, connections for connecting one of said terminalswith one element of one of the dipole aerials of said Adcock aerial system and connections for connecting the other of said terminals with the opposite element of the other dipole aerial of said Adcock aerial system and connections for connecting the remaining upper elements of said dipole aerials and the remaining lower elements of said dipole aerials respectively with one another, the lengths of said connections being such as will provide three signal voltages the vectors of which are disposed 120 degrees apart and have a geometrical sum equal to zero for a predetermined angular setting of the rotary system of aerials with reference to the incoming waves.

6. A radio goniometric receiver set comprisnig an Adcock aerial system including two twoelement dipole aerials, a supplementary two-element dipole aerial positioned outside of the plane of said Adcock aerial system, a single receiver having a pair of input terminals, means for rotating said three aerials around a vertical axis and connections for connecting said terminals of the receiver respectively with opposite elements of each of said dipole aerials, the length of said connections being such as will provide a balanced three-phase system for a predetermined angular setting of the rotary system of aerials with reference to the incoming waves.

'7. A radio goniometric receiver set comprising an Adcock aerial system including two two-element dipole aerials, a supplementary two-element dipole aerial positioned outside of the plane of said Adcock aerial system, a single receiver having a pair of input terminals, means for rotating said three aerials around a vertical axis and connections for connecting said terminals of the receiver respectively with opposite elements of each of said dipole aerials, the lengths of said connections being such as will provide three signal voltages the vectors of which are disposed 120 degrees apart and have a geometrical sum equal to zero for a predetermined angular setting of the rotary system of aerials with reference to the incoming waves.

8. A radio goniometric receiver set comprising an Adcock aerial system including two two-element dipole aerials, a further two-element dipole aerial positioned outside of the plane of said Adcock aerial system and at equal distances from the elementary aerials of said Adcock aerial system, a single receiver having a pair of input terminals, means for rotating said three aerials around a vertical axis, connections for connecting one of said terminals with one element of one of the dipole aerials of said Adcock aerial system and connections for connecting the opposite element the other dipole aerial of said Adcock aerial system with the other of said terminals and connections for connecting the remaining upper aerial elements of said dipoles together and the remaining lower dipole aerial elements together, the lengths of said connections being such as will provide a balanced three-phase system for a predetermined angular setting of the rotary system of aerials with reference to the incoming waves.

9. A radio goniometric receiver set comprising an Adcock aerial system including two two-element dipole aerials, a further two-element dipole aerial positioned outside of the plane of said Adcock aerial system and at equal distances from the elementary aerials of said Adcock aerial system, a single receiver having a pair of input terminals, means for rotating said three aerials around a vertical axis, connections for connecting one of said terminals with one element of one of the dipole aerials of said Adcock aerial system and connections for connecting the opposite element the other dipole aerial of said Adcock aerial system with the other of said terminals and connections for connecting the remaining upper aerial elements of said dipoles together and the remaining lower dipole aerial elements together, the lengths of said connections being such as will provide three signal voltages the vectors of which are disposed degrees apart and have a geometrical sum equal to zero for a predetermined angular setting of the rotary system of aerials with reference to the incoming waves.

10. A radio goniometric receiver set comprising an Adcock aerial system including a pair of twoelement dipole aerials, a supplementary two-element dipole aerial on the outside of the plane of said Adcock aerial system and at equal distances from the elementary aerials of said Adcock aerial system, receiving means having an input circuit. means for rotating said Adcock aerial system and said supplementary aerial around a vertical axis and connections having predetermined lengths for connecting all of said dipole aerials to the input circuit of said receiving means to form a balanced three-phase system for a predetermined angular setting of the rotary system of aerials with reference to the incoming waves.

11. A radio goniometric receiver set comprising an Adcock aerial system including a pair of twoelement dipole aerials, a supplementary two-element dipole aerial on the outside of the. plane of said Adcock aerial system and at equal distances from the elementary aerials of said Adcock aerial system, a single receiver having two input terminals, means for rotating said Adcock aerial system and said supplementary aerial around a vertical axis and connections for connecting said terminals of the receiver respectively with opposite elements of each said dipole aerial, the length of said connections being such as will provide three signal voltages the vectors of which are disposed 120 degrees apart and have a geometrical sum equal to zero for a predetermined angular setting of the rotary system of aerials with reference to the incoming waves.

PIERRE BODEZ.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,105,569 White et al Jan. 18, 1938 2,266,454 Wagstaffe Dec. 16, 1941 2,365,118 Strafiord Dec. 12, 1944 2,426,175 Busignies Aug. 26, 1947 FOREIGN PATENTS Number Country Date 218,661 Great Britain Apr. 2, 1925 432,978 Great Britain Aug. '7, 1935 

